AREA FORMULAS

square = a 2 external image square.gif

rectangle = ab external image rect.gif

parallelogram = bh external image parral.gif

trapezoid = h/2 (b1 + b2) external image trap.gif

circle = pi r 2 external image circle.gif

ellipse = pi r1 r2 external image ellipse.gif


Examples

Square: The area formula of a square is area= a^2.
Both side lenghts of the square is 9.
To find the area you go (area=9^2) or (area=9 sqared).
Therefore the area of a square is 81 square units.

Rectangle: The area formula of a rectangle is area = lw, (length times the width)
If your length is 5 and width is 6
To find the area you go (area=5*6)
Therefore the area is 30 square units.

Parallelogram: The area formula for parallelogram is area= bh, (base times the height).
If your base is 9 and the height is 5.
To find the area you go area=(9*5).
Therefore the area is 45 sqaure units.

Trapezoid: The area formula for a trapezoid is area= (b1+b2)/2*h, ( base1+base2 divided by 2 times the height).
If base1 is 10 and base 2 is 5 and the height is 9.
To find the area you go area=(10+5/2*9).
Therefore the area is 67.5 square units.

Circle: The area formula for a circle is area=(pi)r^2), (pie)(r squared)
If the radius of the circle is 12.
To find the area you go area=(pi)(12^2).
Therefore the area of a circle is 452.16 square units.

Ellipse The area formula for a circle is (pi)(r1*r2), (pie)(times radius1 times radius2)
If radius1 is 5 and radius2 is 10.
To find the area you go area=(pi)(5*10).
Therefore the area of an ellipse is 157 square units